The proposed study will be used as a springboard for Dr. Schwartz to launch a career in HIV prevention research focusing on the joint effects of self and context on HIV risk behaviors (substance use and unsafe sexual behavior) in Hispanic adolescents. The proposed study has three objectives. First, it will provide Dr. Seth Schwartz with valuable mentored experiences. As part of the proposed study, Dr. Schwartz will be mentored in family research, longitudinal research methods, preventive intervention design and implementation, and advanced statistical analyses. Career development will be organized around an exploratory-confirmatory study, using two separate samples. This study will be used to ascertain whether the development of personal and ethnic identity contributes to HIV risk behaviors over and above the contributions made by ecodevelopmental variables. Three specific hypotheses will be tested: (a) changes in ecodevelopmental variables over time predict changes in personal and identity development over time; (b) the development of personal and ethnic identity (both in total and in terms of variability not explained by ecodevelopmental processes) will predict the development of substance use, conduct problems, and unsafe sexual behavior over time; and (c) the Familias Unidas intervention significantly influences the raw personal and ethnic identity scores over time, but the intervention does not influence these scores once variance attributable to ecodevelopmental predictors is factored out. Third, provided that the hypotheses are supported for personal and/or ethnic identity, personal and/or identity development components will be designed to complement the intervention strategies used in Familias Unidas, a family-based prevention program designed to prevent substance use and unsafe sexual behavior in Hispanic immigrant adolescents.